Auto Scaling group capacity providers - Amazon Elastic Container Service
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Auto Scaling group capacity providers

Amazon ECS capacity providers can use Auto Scaling groups to manage the Amazon EC2 instances registered to their clusters. You can use the managed scaling feature to have Amazon ECS manage the scale-in and scale-out actions of the Auto Scaling group or you can manage the scaling actions yourself. For more information, see Amazon ECS cluster Auto Scaling.

Auto Scaling group capacity providers considerations

Consider the following when using Auto Scaling group capacity providers in the classic console:

  • We recommend that you create a new empty Auto Scaling group to use with a capacity provider rather than using an existing one. If you use an existing Auto Scaling group, any Amazon EC2 instances associated with the group that were already running and registered to an Amazon ECS cluster prior to the Auto Scaling group being used to create a capacity provider may not be properly registered with the capacity provider. This may cause issues when using the capacity provider in a capacity provider strategy. The DescribeContainerInstances API can confirm whether a container instance is associated with a capacity provider or not.


    To create an empty Auto Scaling group, set the desired count to zero. After you have created the capacity provider and associated it with a cluster, you can then scale it out.

  • An Auto Scaling group must have a MaxSize greater than zero to scale out.

  • If the Auto Scaling group is unable to scale out to accommodate the number of tasks run, the tasks will fail to transition beyond the PROVISIONING state.

  • When you use managed termination protection, you must also use managed scaling otherwise managed termination protection won't work.

  • When managed scaling is turned on, the Auto Scaling group capacity provider creates a scaling policy resource to manage scaling of your Auto Scaling group. You can identify these resources by the ECSManaged prefix.

  • Do not modify the scaling policy resource associated with your Auto Scaling groups that are managed by capacity providers.

  • You can add a warm pool to your Auto Scaling group. A warm pool is a group of pre-initialized Amazon ECS instances that are ready to be included in the cluster whenever your application needs to scale out. For more information about warm pools, see Using a warm pool for your Auto Scaling group

  • The Auto Scaling group can't have instance weighting settings. Instance weighting isn't supported when used with an Amazon ECS capacity provider.